Automatic packaging structure



Sept. 21, 1965 J. BUECHEK 3,207,285

AUTOMATIC PACKAGING STRUCTURE Filed Sept. 12, 1962 s Sheets-Sheet 1 INVENTOR. JOHN BUECHEK AHQ r2 eys Sept. 21, 1965 J. BUECHEK AUTOMATIC PACKAGING STRUCTURE 5 Sheets-Sheet 2 Filed Sept. 12, 1962 lmxmxdim' "Illlllllllll BY W 111w .gw

iminmn Sept. 21, 1965 Filed Sept. 12, 1962 Fig. 14.

J. BUECHEK AUTOMATIC PACKAGING STRUCTURE Fig. 11.

5 Sheets-Sheet 3 Fig.12. Fig.13.

INVENTOR. JOHN BUECHEK BY fzme Zowwm mm A-H'arneys United States Patent 3,207,285 AUTOMATIC PACKAGING STRUCTURE John Buechek, Indianapolis, Ind., assignor to Grand Duchess Steaks Corporation, Indianapolis, Ind., a corporation of Indiana Filed Sept. 12, 1962, Ser. No. 223,145 4 Claims. (Cl. 198-24) This invention relates generally to automatic packaging apparatus and in particular to apparatus for automatically applying a paperboard card to a prewrapped product such as luncheon meat.

U.S. Patent 2,802,569 discloses and claims a reinforced display package which includes a transparent container or wrapper containing, for example, a meat product, and a reinforcing paperboard blank which is folded about the container but permits display of the container contents. In the past the assembly of such display packages, that is, the depositing and folding of the paperboard element upon the container portion, has been accomplished manually with obvious economic disadvantages or by semi-automatic methods which leave considerable room for improvement.

The primary object of the present invention is to provide an automatic packaging apparatus for completing the assembly of a display package of the type described in the above mentioned patent.

A further object of the present invention is to provide an apparatus for continuously moving objects, such as prepackaged food, in a controlled path over a stationary surface.

These and other objects will become apparent as the description proceeds with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of apparatus embodying the present invention.

FIG. 2 is a fragmentary, perspective view of the apparatus of FIG. I viewed from the front or feeding end.

FIG. 3 is a fragmentary, perspective view of the apparatus similar to FIG. 2 but showing the apparatus at a further stage in the cycle.

FIG. 4 is a fragmentary perspective view similar to FIG. 2 but showing a portion of the cowl or housing removed.

FIG. 5 is a fragmentary view illustrating the action of a cam and cam followers forming a part of the apparatus.

FIG. 6 is a fragmentary perspective view illustrating the action of one of the cam followers shown in FIG. 5.

FIG. 7 is a fragmentary view illustrating the action of another of the cam followers shown in FIG. 5.

FIG. 8 is a fragmentary perspective view illustrating the paperboard component depositing structure.

FIG. 9 is an enlarged, detailed view illustrating a portion of the apparatus.

FIG. 10 is an enlarged, top plan view of a portion of the lower conveyor element.

FIG. 11 is a top plan view of a paperboard blank which is applied to the package by the apparatus of the present invention.

FIG. 12 is a side view of the completed package after it has been processed by the apparatus of the present invention.

FIG. 13 is a top plan View of the completed package shown in FIG. 13.

FIG. 14 is a schematic view illustrating the means for applying power to the conveyor elements.

As set out in the above identified patent and as shown in FIGS. 11-13, the completed package comprises a stack of sliced or unsliced luncheon meat, for example, enclosed by a transparent container or wrapping 10. The

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container 10 protrudes through a window or aperture 11 in a paperboard blank indicated at 12. The blank 12 includes a primary panel 13, panel 14 providing the window or aperture 11 and a side tab 16. The completed package is formed as illustrated in FIGS. 11, 12 and 13 with the panel 13 folded rearwardly along the panel 14 and the tab 16 sealed over the adjacent margin of the panel 13. When so arranged the transparent container 10 protrudes through the window 11 and the rear face (when folded) of the panel 13 provides space for advertising or identifying messages as does the marginal portions of the panel 14. It will be understood that the actual sealing of, for example, the tab 16 and the adjacent edges of the panels 13 and 14 is accomplished by additional machinery not disclosed herein and not form ing a part of the present invention.

Referring now to FIG. 1, the apparatus of the present invention includes vertical frame members 17 and horizontal frame members 18. The frame journals for rotation horizontally spaced shafts 19 and 21. The spaced shafts carry sprockets 22-23 and 24-26, respectively. Extending between the sprockets 22 and 24 is an endless chain 27 and extending between the sprockets 23 and 26 is an endless chain 28.

The end of the shaft 19 adjacent the sprocket 23 carries a larger sprocket 31 which is rotated by a power input chain 32. As may best be seen in FIG. 14, the chain 32 extends around idler sprockets 33, 34 and 36 which are rotatably supported on stub shafts carried by the frame. The chain 32 further extends around a sector of a sprocket 37. The sprocket 37 is carried by a shaft 38 which extends transversely across the frame and is journalled by suitable bearings supported on the frame as shown in FIG. 1. Chain 32 is driven by a power sprocket 39 which is rotated by a power means indicated schematically at 41 in FIG. 14. The power means preferably takes the form of an electric motor which is continuously energized when the apparatus is in use but which is coupled to the sprocket 39 by means of a conventional one-revolution clutch which is actuated by a solenoid controlled by an electric switch to be subsequently described. Since the specific construction of the conventional one-revolution clutch and its solenoid actuator form no part of the present invention they are not described in detail herein. The shaft 38, adjacent the sprocket 37 also carries a cam 42 having a plurality of lobes 43 thereon. The function of the cam 42 will be subsequently described but it should be noted with relation to FIG. 14 that the sprocket 37 and the sprocket 39 are relatively sized so that one revolution of the sprocket 39 is sufficient to move the cam 42 the angular distance between any two of its lobes 43.

As may best be seen in FIG. 8 the space between the chains 27 and 28 is spanned by a series of open-ended enclosures 46 which may be formed of aluminum or similar, suitable material. Each of the conveyors 46 is provided, on its side member adjacent the chains with a de pending bracket 47 which is carried by a plate attached to the adjacent chain link. The chain links adjacent the ends of the enclosures also carry sidewardly extending brackets 48 not attached to the enclosures 46 and which serve 'to support the enclosures in generally horizontal position on the two chains as the chains move through their upper pass, the pivotal connection of the enclosures with the chains permitting the chains to pass over the sprockets as the chains move from their upper to lower passes. Each of the enclosures or platforms 46 have tabs o; abutments 51 extending upwardly from their trailing e ge.

Supported by an auxiliary framework 52, which is dis posed atop the upper horizontal frame members 18 is a stacked supply of the paperboard blanks 12 specifically described with reference to FIG. 11. The stack of paperboard blanks are retained by inwardly projecting abutments (not shown) and blanks or cards are deformed past these abutments and deposited on the upper face 46a of each of the enclosures 46 as it passes beneath the stack of blanks. It will be evident that the blanks are oriented so that their window apertures 11 are directly above the open end of the enclosures 46.

A single blank 12 is deposited on the upper face of each of the enclosures by means of a suction cup 56 which is moved vertically upwardly by a pneumatic cylinder (not shown). The pneumatic cylinder is pressurized so as to move the suction cup 56 vertically upwardly and into engagement with the lowermost blank by means of an air switch or valve 57 (FIG. 7). The actuating dog for the air switch 57 is moved by the end portion 58 of a cam follower 59. As may best be seen in FIG. the cam follower 59 carries a roller 61 which cooperates with the periphery of the cam 42, the cam follower being pivoted at its end opposite the portion 58 upon a stub shaft 62 carried by a bracket 62a (FIG. 7) FIG. 5 shows the cam 42 and followers in their quiescent position prior to the start of a cycle and under these conditions the follower 59 is in a lowered position and the cup 56 is in raised position and in engagement with the lowermost blank. It will thus be evident that each time the cam follower S9 is actuated by a lobe on the cam 42 the suction cup 56 will drop to lower the lowermost blank 12 on the stack and will move it downwardly from the stack and place it on the upper face 46a of the adjacent enclosure 46 with its window aperture registering with the open end of the enclosure. The abutments 51 retain the blank in place on the enclosure as it is moved through the upper pass of the chains 27 and 28.

As may best be seen in FIGS. 2 and 4, stationary retaining means is provided for holding the cards or blanks in place over the enclosures as the chains move around the sprockets 24 and 26. The retaining means comprise members 63 and 64 having inwardly directed marginal areas and are provided with curved spring fingers 66 which hold the blanks against their respective enclosures as the chains 27 and 28 enter their lower pass.

The apparatus so far described functions to place the paperboard blanks on the outer face of each of the enclosures 46 as the chains 27 and 28 begin their lower pass between the sprockets 2427 and 2628. The second conveyor means for moving the transparent container enclosed or prewrapped product into position for joining with the paperboard blank will now be described. This conveyor means is made up of an endless, flexible conveyor element formed by two endless chains 71 and 72 which mesh with spaced parallel sprockets 73 and 74, the sprockets being carried by a common shaft 76 which is journalled on bearings mounted on extensions 18a of the horizontal frame members 18 as may best be seen in FIG. 4. The chain 71 further meshes with a sprocket 77 (FIG. 1) carried by the shaft 38. The chain 72 extends generally parallel to and aligned with the chain 71 and is received on a sprocket 78 (FIG. 6) which is identical to the sprocket 77 and similarly mounted upon the shaft 38. The sprockets 73 and 74 are shielded by a cowl 81 (FIGS. 1 and 2) which has been removed in the showing of FIG. 4 to illustrate the arrangement of the chains and associated parts.

As may best be seen in FIGS. 2, 4 and a stationary plate 82 provides an elongated surface between the upper pass of the chains 71 and 72, the surface provided by the plate 82 being disposed generally horizontally but curving downwardly out of the major plane of the surface as indicated at 82b in FIG. 4. The plate 82, at its end opposite the curved end 82b is provided with a transverse slot 83 (FIGS. 9 and 10) and beyond the slot 83 an exten sion 82a of the plate 82 protrudes beyond the sprockets 22 and 23 as shown in FIG. 1. The transverse slot or aperture 83 disposed between the plate 82 and its extension 82a is located adjacent the extreme end portion 63a of the stationary member 63 indicated in FIG. 3. The sprockets 73 and 74 rotate clockwise as viewed in FIG. 4 upon movement of the chains 71 and 72, the power input to the system being provided by the shaft 38 upon which the sprockets 77 and 78 are mounted. It will thus be evident that the conveyor element formed by the chains 71 and 72 and associated parts extends on its upper pass to an area of substantial tangency with a portion of the lower pass of the conveyor element formed by the chains 27 and 28.

Spanning the space between the chains 71 and 72 are a series of spaced, generally U-shaped elements indicated generally at 91 in FIG. 10. The elements 91 are formed of leg portions 92 and a transverse or web portion 93. As will be evident from FIGS. 9 and 10 the web portion 93 is offset somewhat from the leg portions 92 and the leg portions taper inwardly to permit nesting of the elements 91 as the chains upon which the elements are supported move through certain portions of their paths. Certain of the chain elements are provided with flanges 70 carrying pins 70a upon which the free ends of the legs 92 of the elements 91 are pivoted.

As will be evident from FIG. 10, as the chains 71 and '72 move along the surface 82 so as to draw the transverse portion 93 of the members 91 over the surface 82, the abutments provided by the transverse portions 93 will serve to sweep along the length of the surface and slide objects, such as the packaged meat products referred to herein, along the surface. While the transverse or web portions 93 of the members 91 are arranged so as to move along the upper face of the surface 82, the web portions 93 leave the surface 82 at the slot 83 and do not traverse the extending portion 82a of the surface.

The gap formed by the slot 83 is normally bridged or filled by the upper face of a shoe element 94 as illustrated in solid lines in FIG. 9. The shoe 94 is supported by spaced legs 96 which are rigidly fastened to, and extend radially from, a shaft 97 which is journalled at one end in the lower horizontal frame portion 18 as indicated in FIG. 3. The opposite end portion of the shaft 97 carries a rigidly attached link 98 (FIG. 5) which, in turn, is mechanically linked by the member 99 to one end of a cam follower 101. As will be evident from FIG. 5, the cam follower 101 carries a roller 102 which cooperates with the periphery of the cam 42, the follower lever 101 being pivoted at 103. The upper end of the follower lever 101 is attached by means of the link 104 (FIGS. 5 and 6), the lower end of the link 104 actuating a card or blank folding element 106 which functions to fold portions of the card about the product container as will subsequently be described. As will be evident from FIGS. 5 and 9 as the follower 101 is actuated by a lobe 43 on the cam 42 the shaft 97 will be given an angular impulse which will serve to momentarily deflect the shoe 94 to its broken line position of FIG. 9.

With the transverse or web portions 93 of the members 91 removed from the surface 82, the chains 71 and 72 may proceed through their lower pass. Referring again to FIG. 4, it will be evident that adjacent the lower margin of the sprockets 73 and 74 the elements 91 are disposed so that the transverse or web portion 93 of the elements trails behind the pivotal attachment of the free end of the legs to the chains, with the web portion 93 sliding along the stationary retainer plate 106. As the members 91 are moved upwardly with the progress of the chains around the sprockets 73 and 74 the web portion 93 will slide atop the end of the curved portion 82b of the surface 82 and will proceed to wipe the face of the surface 82.

As may best be seen in FIG. 2 a plate '107 is supported adjacent to but spaced sidewardly from the surface 82 and this plate 107 carries brackets which support an upstanding abutment 108 adjacent the edge of the surface 82. The abutment 108 is adapted to stop the downward motion of a prewrapped or transparen container enclosed product as indicated at 109 in FIG. 2. The product 109 is deposited on the surface 82 at intervals either manually or by suitable automatic machinery. As here shown the delivery of the product 109 to the surface 82 is accomplished by means of the tension springs 111 which are moved by a rotating spindle 112 and serve to project a product dropped at the upper end of the conveyor thus formed (the product so dropped being indicated at 10911 in FIG. 2) onto the surface 82 and against the locating abutment 108. As each prewrapped or container enclosed product moves into place on the surface 82 it actuates upwardly the free end of an arm 113. Actuation of the arm upwardly through a small distance serves to actuate the electrical switch 114, the switch 114 controlling energization of the solenoid operated, one-revolution clutch mechanism previously referred to. The switch 114 thus starts a cycle of motion of the apparatus, the cycle being terminated by the disconnection of the one revolution clutch regardless of the subsequent condition of the switch 114. As will be evident from FIG. 2 with the start of rotation of the sprockets, after actuation of the switch 114, the transverse portions 93 of the members 91 will move he product 109 along the surface 82 and toward the point of substantial tangency of the two conveyor systems. A resilient member 116 serves to retain the product 109 tightly against the surface 82 as the product enters the tangency area. As the product enters this area it will be evident, particularly from FIG. 2 that a paperboard blank, such as shown at 12 in FIG. 2, will be deposited over the product 109 with the product extending through the window aperture 11 of the blank 12 and upwardly into the corresponding enclosure 46. Subsequently the enclosure and the web portion 93 of the members 91 move the product and card along the surface 82, over the shoe 94 (FIG. and onto the surface extension 82a. As the web portion 93 of the particular member 91 involved reaches the shoe 94, the angular impulse provided to the shaft 97 pivots the shoe to its broken line position of FIG. 9 thereby uncovering the slot 83 and permitting the web portion 93 of the member 91 to fall downwardly through the slot. After the removal of the particular member 91 from the line of motion of the product, continued movement of the product and the card disposed thereon along the surface 82a is accomplished by the closures 46. As will be evident from FIG. 1 as the product and the card deposited thereon are moved along the surface 82a by the enclosures 46, the flap 16 and panel 13 of the blank 12 is folded about the product to provide the finished package of FIGS. 13 and 14. As may best be seen 1n FIGS. 1 and 3 an element 118 having a pointed end portion 119 is stationarily mounted so as to extend toward the area of substantial tangency of the two conveyors and as the enclosures 46 are moved toward the member 118 the pointed end 119 enters the slot 46b formed along the upper face of one side margin of each of the enclosures 46. The pointed end portion 119 of the member 118 moves through the slot 46b and folds downwardly the flap 16 on the paperboard blank 12. Plough elements of suitable configuration such as indicated at 121 in FIG. 1, disposed further along the surface 82a and acting in conjunction with the member 106 described with reference to FIG. 6 serve to complete the folding of the panel 13 and flap 16 about the product, the precise shape of the ploughs and sequence of folding not being described in detail herein since they specifically form no part of the present invention. As will be evident from FIG. 1, the completely packaged product, appearing as shown in FIGS. 12 and 13, is finally deposited at the end of the surface 82a from which it may be removed either manually or by suitable automatic machinery.

In operation, it will be understood that since the area of substantial tangency of the two conveyor systems, that is, the area in which the paperboard blank is joined to the product, is separated from the areas at which the paperboard blanks are deposited on the enclosures 46 and the area of deposit of the product on the surface 82, upon initial start-up of the apparatus the switch 114 must be actuated several times before completed, packaged products appear at the terminal end of the surface 82a. It will be further evident from the foregoing description that the various sprockets and the conveyors formed by the chains accommodated on the sprockets do not operate continuously but are cycled through motion increments initiated by actuation of the switch 114 but terminated automatically by the one-revolution clutch connecting the power means 41 to the drive sprocket 39 of 'FIG. 15. The finished, packaged product is formed by bringing together the paperboard blank component and the wrapped product component on separate endless conveyors which approach each other at a point of substantial tangency where the product components are joined. The members 91 and the arrangement by means of slot 83 whereby the web portion 93 of the members 91 may be removed from the surface 82 to permit the travel of the members 91 along the lower pass of the chains 71 and 72, and the disposition of the web portions 93 atop the surface 82 at the curved section 82a form primary features of the present invention. It will be understood that some of the features of the present invention might be retained in a structure which utilized endless, flexible means other than chains as components of the two conveyor systems.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and Within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

1. A conveyor for moving objects such as prepackaged food over a stationary surface comprising means providing an elongated flat surface disposed generally horizontally but curving downwardly out of the major plane of the surface at one end thereof, said surface having a transyerse slot therein remote from said One end, a pair of spaced sprockets coaxially mounted for rotation with the axis of rotation of said sprockets passing parallel to and within the bight of said curved surface, a flexible chain carried by each of said sprockets, said chains being movable npon sprocket rotation in an upper pass which is adjacent and parallel to the margins of said elongated surface and in a direction proceeding from said curved end toward said slotted end thereof, power means for moving said chains and rotating said sprockets, and a series of spaced, generally U-shaped elements each having the free end of one leg pivotally secured to one of said chains and the free end of the other leg pivotally secured to the other chain with the Web portion of the elements spanning the space between said chains, whereby as said elements are moved by said chains past said one end of said curved surface said web portions of said U-shaped elements are deposited on the upper face of said elongated surface and said web portions sweep said upper face as said chains move through their upper pass, said web portions dropping from said elongated surface through said transverse slot as said U-shaped elements are moved past said slot, and a member supported adjacent said transverse slot and adapted for movement into a position closing said slot after a web portion has dropped therethrough.

2. A conveyor for moving objects such as prepackaged food over a stationary surface comprising means providing an elongated fiat surface disposed generally horizontally but curving downwardly out of the major plane of the surface at one end thereof, said surface having a transverse slot therein remote from said one end, a pair of spaced rotatable elements mounted for rotation with the axis of rotation passing parallel to and within the bight of said curved surface, a flexible member carried by each of said rotatable elements, said flexible members being movable upon rotation of said rotatable elements in an upper pass which is adjacent and parallel to the margins of said elongated surface and in a direction proceeding from said curved end toward said slotted end thereof, power means for moving said flexible members and rotating said rotatable elements, and a series of spaced, generally U-shaped elements each having the free end of one leg pivotally secured to one of said flexible members and the free end of the other leg pivotally secured to the other flexible member with the web portion of the elements spanning the space between said members, whereby as said U-shaped elements are moved by said flexible members past said one end of said curved surface said web portions of said U-shaped elements are deposited on the upper face of said elongated surface and said web portion-s sweep said upper face as said flexible members move through their upper pass, said web portions dropping from said elongated surface through said transverse slot as said U-shaped elements are moved past said slot, and a member supported adjacent said transverse slot and adapted for movement into a position closing said slot after a web portion has dropped therethrough.

3. A conveyor for moving objectssuch as prepackaged food over a stationary surface comprising means providing an elongated flat surface disposed generally horizontally but curving downwardly out of the major plane of the surface at one end thereof, said surface having a transverse slot therein remote from said one end, a pair of spaced sprockets coaxially mounted for rotation with the axis of rotation of said sprockets passing parallel to and within the bight of said curved surface, a flexible chain carried by each of said sprockets, said chains being movable upon sprocket rotation in an upper pass which is adjacent and parallel to the margins of said elongated surface and in a direction proceeding from said curved end toward said slotted end thereof, power means for moving said chains and rotating said sprockets, and a series of spaced, generally U-shaped elements each having the free end of one leg pivotally secured to one of said chains and the free end of the other leg pivotally secured to the other chain with the Web portion of the elements spanning the space between said chains, whereby as said elements are moved by said chains past said one end of said curved surface said web portions of said U- .shaped elements are deposited on the upper face of said elongated surface and said web portions sweep said upper face as said chains move through their upper pass, said web portions dropping from said elongated surface through said transverse slot as said U-shaped elements are moved past said slot, said web portions of said U- shaped elements having a length dimension substantially less than the transverse distance between said leg ends so that said U-shaped elements may nest as said chains pass over said sprockets.

4. A conveyor for moving objects such as prepackaged food over a stationary surface comprising means providing an elongated flat surface disposed generally horizontally but curving downwardly out of the major plane of the surface at one end thereof, said surface having a transverse slot therein remote from said one end, a pair of spaced rotatable elements mounted for rotation with the axis of rotation passing parallel to and within the bight of said curved surface, a flexible member carried by each of said rotatable elements, said flexible members being movable upon rotation of said rotatable elements in an upper pas-s which is adjacent and parallel to the margins of said elongated surface and in a direction proceeding from said curved end toward said slotted end thereof, power means for moving said flexible members and rotating said rotatable elements, and a series of spaced, generally U-shaped elements each having the free end of one leg pivotally secured to one of said flexible members and the free end of the other leg pivotally secured to the other flexible member with the web portion of the elements spanning the space between said members, whereby as said U-shaped elements are moved by said flexible members past said one end of said curved surface said web portions of said U-shaped elements are deposited on the upper face of said elongated surface and said web portions sweep said upper face as said flexible members move through their upper pass, said web portions dropping from said elongated surface through said transverse slot as said U-shaped elements are moved past said slot, said web portions of said, U-shaped elements having a length dimension substantially less than the transverse distance between said leg ends so that said U-shaped elements may nest as said flexible members pass over said rotatable elements.

References Cited by the Examiner UNITED STATES PATENTS 757,667 4/04 Mayall 198-170 X 1,557,574 10/25 :Ferguson et a1 53-156 2,208,776 7/40 Sandberg 53l56 2,253,367 8/41 Prima '19 8170 X 2,891,659 6/59 Westeren 198-221 2,896,775 7/59 Ipsen 198221 SAMUEL F. COLEMAN, Primary Examiner.

TRAVIS S. MCGEHEE, EDWARD A. SROKA,

Examiners. 

1. A CONEYOR FOR MOVING OBJECTS SUCH AS PREPACKAGED FOOD OVER A STATIONARY SURFACE COMPRISING MEANS PROVIDING AN ELONGATED FLAT SURFACE DISPOSED GENERALLY HORIZONTALLY BUT CURVING DOWNWARDLY OUT OF THE MAJOR PLANE OF THE SURFACE AT ONE END THEREOF, SAID SURFACE HAVING A TRANSVERSE SLOT THEREIN REMOTE FROM SAID ONE END, A PAIR OF SPACED SPROCKETS COAXIALLY MOUNTED FOR ROTATION WITH THE AXIS OF ROTATION OF SAID SPROCKETS PASSING PARALLEL TO AND WITHIN THE BIGHT OF SAID CURVED SURFACE, A FLEXIBLE CHAIN CARRIED BY EACH OF SAID SPROCKETS, SAID CHAINS BEING MOVABLE UPON SPROCKET ROTATION IN AN UPPER PASS WHICH IS ADJACENT AND PARALLEL TO THE MARGINS OF SAID ELONGATED SURFACE AND IN A DIRECTION PROCEEDING FROM SAID CURVED END TOWARD SAID SLOTTED END THEREOF, POWER MEANS FOR MOVING SAID CHAINS AND ROTATING SAID SPROCKETS, AND A SERIES OF SPACED, GENERALLY U-SHAPED ELEMENTS EACH HAVING THE FREE END OF ONE LEG PIVOTALLY SECURED TO ONE OF SAID CHAINS AND THE FREE END OF THE OTHER LEG PIVOTALLY SECURED TO THE OTHER CHAIN WITH THE WEB PORTION OF THE ELEMENTS SPANNING THE SPACE BETWEEN SAID CHAINS, WHEREBY AS SAID ELEMENTS ARE MOVED BY SAID CHAINS PAST SAID ONE END OF SAID CURVED SURFACE SAID WEB PORTIONS OF SAID U-SHAPED ELEMENTS ARE DEPOSITED ON THE UPPER FACE OF SAID ELONGATED SURFACE AND SAID WEB PORTIONS SWEEP SAID UPPER FACE AS SAID CHAINS MOVE THROUGH THEIR UPPER PASS, SAID WEB PORTIONS DROPPING FROM SAID ELONGATED SURFACE THROUGH SAID TRANSVERSE SLOT AS SAID U-SHAPED ELEMENTS ARE MOVED PAST SAID SLOT, AND A MEMBER SUPPORTED ADJACENT SAID TRANSVERSE SLOT AND ADAPTED FOR MOVEMENT INTO A POSITION CLOSING SAID SLOT AFTER A WEB PORTIONS HAS DROPPED THERETHROUGH. 